Process of making sulfuric anhydrid.



H. HOWARD.

PROCESS 0F MAKING SULFURIG ANHYDRID.

APPLICATION FILED-001221, 1909.

Patented June 11, 1912.

HENRY HOWARD, 0F BOSTON, MASSACHUSETTS.

rnocnss 6r MAxINe sunrunrc ANHYDBID.

Slpecication of Letters Patent.

Patented June 11, 1912.

Application filedl October 21, 1909. Serial No. 523,808.

To all whom 'it may concem:

Be it known that I, HENRY HOWARD, a citizen` of the United States, residing at Boston, in the 'county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Sulfuric Anhydrid, of which ,the followmg'is a specification.

This invention relates to the lmanufacture of sulfuric anhydrid from sulfur dioxid gas by the well known contact process. In the practice of' this process, it has heretofore been the lcustom to dry the purified gases on their way to the contact chamber 'by' passing them through a tower or other apparatus in which they were brought into contact with concentrated sulfuric acid. The strong acid used for this purpose soon becomes diluted, particularly in summer, when the air contains a com aratively large 'amount of moisturey and t is consumption of strong acid in this drying operation substantially reduces the amount available for sale.

The present invention consists in drying the gases before their conversion into sulfuric anhydrid by cooling them to a pointl at which the moisture contained therein will fio be condensed and.precipitated, the cooling being elected by passing the gases through any suitable refrigerating apparatus. The refrigeration of the gas has the further advantage that the effective capacity of the blowing or suction apparatus used to force the gases through the various apparatus will be increased almost in direct proportion to the lowering of the absolute temperature,

thereby effecting a still rfurther economy in the cost of manufacture.

. In the refrigeration of the gas, the cooling may be carried to a temperature so low as case the gas is conducted into the contact apparatus without passing through a sulfuric acid drying tower. Or thegas may be first cooled in the refrigerating apparatus to a temperature at which the greater part of the moisture condenses, and is then passed into a dryin tower where the residual moisture is -absor ed by strong acid.

Referring to the drawing, which is diagrammatic in character, the purified SO2 gases are passed through the refrigerator and thence either directly to the compressor by which they are delivered to the contact apparatus; or they pass from the refrigerator to a drying tower and thence to the compressor, suitable valves 1, 2, B, to control the flow of gases being located in the pipes, .as shown. Y

No particular forms of apparatus are illustrated, as they may be of any of the well known types ofdevice used for the purposes indicated. v

I claim: y

1f. the process of making sulfuric anhy drid, the method which consists in refriger' ating gases containing sulfur-dioxid to remove substantially all'thev moisture therefrom, andthen converting the thus dried sulfur-dioxid into sulfuric anhydrid by the contact process.

2. In the process of making sulfuric anhydrid, the method which consists in refriger'f In testimony whereof, I aiiix my signature witnesses.

, HENRY HOWARD. Witnesses W. B. KEITH, EDWIN R. BOND.

in presence of two 

